Fuse construction



Dec. 23, 1941. R. R. PITTMAN ETAL FUSE CONSTRUCTION Filed Jan. 29, 194055...; I ll:

INVENTORS 96 Q (2W4 M M Patented Dec. 23, 1941 FUSE CONSTRUCTION RalphE. Pittman and Carroll B. Walsh,

Pine Bluff, Ark.

Application January 29, 1940, Serial No. 316,147 8 Claims. (Cl. 200-111)This invention relates generally to fuse switches, and particularly tohigh voltage fuse switches commonly employed for connecting electricalapparatus to distribution circuits.

Among the objects of the invention may be noted the provision of aresilient mounting for the fuse link of the switch in which the switchis in the open circuit position, together with means for moving the fuselink to and establishing the fusible element in the closed circuitposition, in which the fuse link is maintained under tension whenunfused; and the provision of means for testing the connected circuit bytemporarily connecting the fuse link in the circuit without moving it tothe normal closed circuit position. Other objects will be obvious, or inpart pointed out hereinafter.

The invention comprises the elements and combinations thereof, featuresof construction, and arrangement of parts to be exemplified in thedescription to follow, and the scope of the invention will be indicatedin the accompanying claims.

Fuse switches heretofore in general use which have embodied atensionedfuse link have been objectionable for the reason that the insertion offuse link completed the circuit, while the link itself must pull apartupon fusing in order to interrupt a relatively high current in thecircuit. This construction was such that an operator was required tolook directly at the device in order to insert the link, with theprobability that the fuse link might be blown upon completion of thecircuit. The intensely bright are attending the fusing of the link wasnot only a hazard to the eyes of the operator, but flying fragmentsincident to the fracture of the more or less frangible wall of thefusible element housing were also dangerous.

The present invention embodies a simple arrangement for inserting thefuse link without completing the circuit, and means for testing theconnected circuit by an operator s positioned as to be exposed to nohazard before finally establishing the fuse link in the normal closedcircuit position.

In the drawing: Fig. 1 is a side elevational view of the device; andFig. 2 is a front elevational view of the fuse link, shown partly insection, together with fragmentary portions of the fuse link mountingmembers.

Similar reference characters indicate corresponding parts in the figuresof the drawing.

Referring first to Fig. 1, the longitudinally extending insulator II isprovided near its midpoint with a mounting bracket Hi, the latter beingonly partly shown. The upper end of the insulator l l is encircled by aportion of the resilient conducting switch arm l8, which is clamped inposition on the insulator H by means of the cap screw 26 in cooperationwith the line terminal clamp I3, and extends outwardly therefrom firstin the form of a loop 40, to supply additional resilience, thenceoutwardly, downwardly and upwardly to provide the depression 28, andterminates at'its outermost end in the form of an upwardly turned hook29. The line terminal clamp also extends upwardly to a point above theresilient conducting member l8, and is provided with a line terminalconnector I for the purpose of electrically connecting the lineconductor l2 to the resilient conducting member If.

At the lower end of the insulator II is rigidly attached, in anysuitable manner, as by the encircling band 25, the lower fuse linksupporting member 23, which is of non-resilient construction, and whichextends outwardly from the insulator H in substantially parallelrelationship with the resilient member [8. The outermost end of themember 23 is formed as a downwardly turned hook 24, and the latter ispositioned somewhat nearer the insulator H than is the de' pression, orfuse link engaging portion 28, of the resilient member l8. At someconvenient point near the insulator H, the lower fuse link supportingmember 23 is provided with the load terminal l6 and the connector H, thelatter two elements cooperating to establish electrical connection ofthe load conductor I5 to the lower fuse link supporting member 23.

In addition to the members at the respective ends of the insulator II,the intermediate fuse link supporting member i9 is also rigidly mounted,in any suitable manner, on the insulator H, at a point therebetween andadjacent to the member l8 but insulated from both of the end members I8and 23 respectively. The intermediate member 19 extends outwardly inapproximately parallel relationship with the end members l8 and 23, andis preferably of the same length as the latter. The outermost endportion of the intermediate member I! is formed into an upwardly turnedhook 20, across the opening of which is mounted the resilient tensioningmember 2|, the latter being mounted on the support 22 and arranged toresist deflection in a downward direction.

The fuse link 21, shown in detail in Fig. 2, includes the frangibletubular casing of insulat ing material 30, the respective ends thereofbeing closed by the metal plugs 3| and 32, by means of cooperatingthreads on the respective members. A fusible element 33 spans the plugs3| and 32 within the tube 30, being conveniently secured at itsrespective ends by soldering. Extending endwise from each end of thetube 30, and fastened respectively to the plugs 3| and 32, are theflexible connecting wires 34 and 35, the outer ends being fastenedrespectively to the terminal members 36 and 31. The latter are formedinto closed loops, conveniently circular in section, one end of wireforming the loops extending respectively above and below the terminalmembers 36 and 31 and being bent to form the hooked portions 38 and 39,the opening of each of the hooked portions facing toward the remainingportions of the fuse link.

To explain the manner of operation of the device, it is first assumedthat no fuse link is mounted on the device, and that it is desired toconnect the terminals through a fuse link. Through manipulation of thefuse link by a suitable insulated tool, the loop 36 may be placed on theresilient member 2| of the hook 20. The tool is then engaged with thelower hook 39 of the fuse link, the link pulled downwardly against thebias of the spring 2!, and the lower loop 3i engaged with the lower hook24. The fuse link and the resilient switch arm 3 now occupy the positionshown by the dashed lines of Fig. 1. It may be noted that in thisposition the terminals I3 and I6 are not connected through the fuselink.

The hooked portion 29 is next engaged with the insulated tool, and themember I8 is preferably pulled down until it contacts some point on thetop surface of the hooked portion 38 of the fuse link 21. This is a testproceeding used to determine the condition of the connected circuit, andmay be readily done while the operators eyes and face are averted, andwhile the operator is at a safe distance from the fuse link should thelatter explode in response to excessively high abnormal current due to adefective or faulty connected circuit.

If the test indicates that the fuse link will not be blown when theterminals are connected, the member I8 is moved slightly laterally anddownwardly to a point from which it may enter the hooked portion 38, andthe member l8 then released. The hooked portion 38 then slides outwardlyalong the downwardly sloping portion of the member I8 until it is seatedin the fuse link engaging depression 28. This is the normal operatingarrangement of the elements when the device is in service, the member [8having cooperated with the fuse link 21 to effect the switching of thedevice from the open circuit position to the closed circuit position, orto effect the moving of the fuse link from the open to closed circuitpositions; in the latter position the fuse link being tensioned by thetendency of the switch arm l8 to return to the relaxed positionindicated by the dashed lines.

Upon the passage of sufiicient current through the fuse link while it isin the normal service position, the frangible cartridge 30 is fractured,and the elements of the fusible portion of the fuse link pulled apartunder the bias of the resilient switch arm l8. In addition, the loopedportion 31 falls by gravity from its position on the lower fuse tubesupport 23. These events all combine to assure prompt circuitinterruption, as well as easily visible indication that the fuse linkhas been blown.

, In the event it is desired, for any reason, to remove the fuse linkfrom the normal service position, this may be readily accomplished bydisengaging the loop 31 from the lower hook 24 by pulling downwardly andoutwardly the lower hooked portion 39 of the fuse link 27, and thenunhooking the link from the member l8.

From the above description, it will be apparent that the several objectsof the invention are simply and economically accomplished. It is obviousthat changes and modifications may be made therein without departingfrom the spirit and scope of the invention, and it is intended that ourdescription shall be interpreted as illustrative rather than limiting.

We claim, as our invention:

1. A fuse construction for use with an electric circuit comprising aninsulator, a resilient conducting member mounted on said insulator, afuse link removably supported at its respective ends on said insulatorin an initial position out of said circuit, and means responsive to apredetermined movement of said conducting member for bodily moving saidfuse link from the initial position to a final position in which saidfuse link is connected in said circuit.

2. A fuse construction comprising insulating means supporting spacedterminals and fuse link supporting means including a fuse linksupporting member which is insulated with respect to said terminals, afuse link mounted on said fuse link supporting means, a resilientconducting member mounted on said insulating means and electricallyconnected to one of said terminals, and means responsive to apredetermined movement of said conducting member for removing said fuselink from said supporting member and electrically connecting saidterminals through said fuse link.

3. A fuse construction comprising insulating means supporting spacedinsulated terminals and fuse link supporting means including a memberwhich is insulated with respect to said terminals,

a fuse link mounted on said supporting means and so arranged that saidterminals are not electrically connected through said fuse link, aresilient conducting member mounted on said insulating means andelectrically connected to one of said terminals, and means responsive toa predetermined movement of said conducting having an open and a normaloperating closed position in series circuit relation with said fuselink, said elements including a portion of said fuse link and aresilient switch arm mounted on said insulating means, the arrangementbeing such that said switch arm'tensions said fuse link only when saidswitch is in the normal operating closed position.

5. A fuse construction comprising insulating means, an upper resilientswitch arm, an intermediate fuse supporting member, and a lower fusesupporting member all mounted in spaced insulated relation to each otheron said insulating means, line and load terminals electrically connectedrespectively to said switch arm and said lower fuse supporting member,and means for resiliently supporting a fuse link on said fuse supportingmembers in insulated relationship with said switch arm, said fuse linkhaving its upper end portion constructed and arranged to cooperate withsaid switch arm in response to a predetermined movement thereof so as toeffect removal of said fuse link from said intermediate supportingmember and electrically connect said line and load terminals throughsaid fuse link.

6. A fuse construction comprising an insulator, an upper resilientswitch arm and a lower rigid fuse link supporting member mounted at therespective ends of said insulator, an intermediate fuse supportingmember mounted in spaced insulated relation on said insulator betweensaid switch arm and said lower fuse supporting member, and means forresiliently mounting a fuse link on said fuse supporting members ininsulated relationship with said switch arm, said fuse link having itsupper end portion extending above said intermediate fuse supportingmember, said upper end portion being bent to provide a hook arranged tocooperate with said switch arm in response to a predetermined movementthereof so as to effect removal of said fuse link from said intermediatesupporting member and electrically connect said switch arm and saidlower fuse supporting member.

7. A fuse construction comprising an insulator, an upper resilientswitch arm and a lower rigid fuse link supporting member mounted at therespective ends of said insulator, an intermediate fuse supportingmember mounted in spaced insulated relation on said insulator betweensaid switch arm and said lower fuse supporting member, and means forresiliently mounting a fuse link on said fuse supporting members ininsulated relationship with said switch arm, said fuse link having itsupper end portion extending above said intermediate fuse supportingmember, said upper end portion being bent to provide a hook arranged tocooperate with said switch arm in response to a predetermined movementthereof so as to effect removal of said fuse link from said intermediatesupporting member and position said fuse link so as to span said switcharm and said lower fuse link supporting member.

8. A fuse construction comprising an insulator, an upper resilientswitch arm and a lower rigid fuse link supporting member mounted at therespective ends of said insulator, an intermediate fuse supportingmember mounted in spaced insulated relation on said insulator betweensaid switch arm and said lower fuse supporting member, and means forresiliently mounting a fuse link on said fuse supporting members ininsulated relationship with said switch arm, said fuse link having itsupper end portion extending above said intermediate fuse supportingmember, said upper end portion being bent to provide a hook arranged tocooperate with said switch arm in response to a predetermined movementthereof so as to effect removal of said fuse link from said intermediatesupporting member and tension said fuse link between said switch arm andsaid lower fuse link supporting member.

RALPH R. PI'I'I'MAN. CARROLL H. WALSH.

